Discoverer 20
| Mission type | Optical reconnaissance |
|---|---|
| Operator | US Air Force/NRO |
| Harvard designation | 1961 Epsilon 1 |
| COSPAR ID | 1961-005A |
| SATCAT no. | 00083 |
| Spacecraft properties | |
| Spacecraft type | KH-5 Argon |
| Bus | Agena-B |
| Manufacturer | Lockheed |
| Launch mass | 1,110 kilograms (2,450 lb) |
| Start of mission | |
| Launch date | 17 February 1961, 20:25 UTC |
| Rocket | Thor DM-21 Agena-B 298 |
| Launch site | Vandenberg SLC-1 launch pad 75-3-4 |
| End of mission | |
| Decay date | 28 July 1962 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Perigee altitude | 283 kilometers (176 mi) |
| Apogee altitude | 770 kilometers (480 mi) |
| Inclination | 80.9 degrees |
| Period | 95.2 minutes |
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Discoverer 20, also known as Corona 9014A, was an American area survey optical reconnaissance satellite which was launched in 1961. It was a KH-5 Argon satellite, based on an Agena-B.[1] Discoverer 20 was the first KH-5 to be launched, however it failed towards the end of its mission, when its film return capsule failed to separate from the main spacecraft.
The launch of Discoverer 20 occurred at 20:25 UTC on 17 February 1961. A Thor DM-21 Agena-B rocket was used, flying from Launch pad 75-3-4 at the Vandenberg Air Force Base.[2] Upon successfully reaching orbit, it was assigned the Harvard designation 1961 Epsilon 1.
Discoverer 20 was operated in a low Earth orbit, with a perigee of 283 kilometres (176 mi), an apogee of 770 kilometres (480 mi), 80.9 degrees of inclination, and a period of 95.2 minutes.[3] The satellite had a mass of 1,110 kilograms (2,450 lb),[4] and was equipped with a frame camera with a focal length of 76 millimetres (3.0 in), which had a maximum resolution of 140 metres (460 ft).[5] Images were recorded onto 127-millimeter (5.0 in) film, and were to have been returned in an SRV before the satellite ceased operations. Due to a problem with the systems controlling the flight program, the spacecraft failed to eject its film capsule, and hence no images were returned.[4] Discoverer 20 decayed from orbit on 28 July 1962.[3]
References
- ^ Krebs, Gunter. "KH-5 Argon (Agena-B based)". Gunter's Space Page. Retrieved 22 June 2010.
- ^ McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 22 June 2010.
- ^ a b McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved 22 June 2010.
- ^ a b Wade, Mark. "KH-5". Encyclopedia Astronautica. Retrieved 22 June 2010.
- ^ "Corona". Mission and Spacecraft Library. NASA. Retrieved 22 June 2010.
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